Intelligent design is a method intended to replace science by Christian belief-based principles. After all, Tinkerbell was brought back to life by believing, so that alone should be proof enough.
Despite God being all-knowing and all-powerful, certain Christians who naturally flunked their science courses in school have decided to take matters into their own hands to insure the right things are being taught to their children. They are confident in throwing aside that fact that God is wholly responsible for the discoverers that built up the body of scientific knowledge as known today. Plus, any number of Jews and Muslims might have snuck a fast one in there somehow. So with the full assurance that Christians are smarter than the God that created them and that Jesus is on their side, Christians then created Intelligent design.